1. Field of the Invention
The present invention relates to a drive force transmission device, applied to a vehicle drivetrain, in which a dry clutch for connecting and disconnecting drive force transmission is disposed within a closed space.
2. Background Information
A hybrid drive force transmission device in which an engine, a motor, a clutch unit, and a transmission unit are coupled and connected to each other is known in the art. For the motor and the clutch unit, a dry multi-plate clutch is disposed inside an electric motor. Specifically, there are provided a clutch hub coupled to an output shaft of the engine, a clutch drum to which a rotor of the electric motor is affixed and which is coupled to an input shaft of the transmission, and a dry multi-plate clutch interposed between the clutch hub and the clutch drum (see, for example, Unexamined Japanese Patent Application Publication No. 2010-151313).